Questions tagged [simulation]

Simulation is the imitation of the operation of a real-world process or system over time.

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7
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1answer
228 views

Issues with modeling pulses in a very simple system of DAEs

Bug introduced in 10.4.1 or earlier and fixed in 11.0.0 Bug has been confirmed by WRI [Case:3594387]: It does appear that the NDSolve function is not behaving properly in this case and an incident ...
4
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2answers
2k views

Calculate $\pi$ using Monte Carlo methods

I know that we can have an estimate of $\pi$ using Monte Carlo methods. I know that we make a huge loop and each time we take randomly two numbers in the range [0,1] and calculate the number of ...
8
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3answers
457 views

Simulation with two random walkers on a lattice with periodic boundaries

I am having some difficulties implementing a Monte Carlo simulation in order to compare the results to analytical calculations. The following code simulates a case with one random walker and a ...
-1
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1answer
173 views

Periodic boundary conditions for two walkers

For some reason I'm getting infinite loops most of the time i run this. Perhaps the periodic boundary conditions are wrong. Seems like the probability of the two positions to be the same is extremely ...
-5
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1answer
405 views

Simulating a “Coin Tossing” Game

i was wondering if i could simulate the following Coin-tossing-game in Mathematica: Two Persons are playing "Coin-tossing" against each other. If one wins, he gives one Dollar to the other. Game ...
24
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1answer
757 views

How to model wooden joints with mathematica's FEM?

This is a dovetail joint: and I'd like to see the stresses and deformation on the joint.I haven't seen any modeling of disconnected regions with FEM, only connected regions, so I'm curious if you can ...
11
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1answer
513 views

Beam deformation due to localized force distribution

I would like to simulate the deformation of a beam which is fixed on one end and has some localized forces applied along the top. I have been inspired by this Mathematica example: http://www....
1
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1answer
874 views

How to add moon to orbit Earth that Orbit Sun

I want to add moon(Blue) that orbiting earth(Red). while Earth is orbiting Sun. this is my code so far that consist of earth, sun and moon. how to write a code so that Moon is orbiting earth instead ...
29
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1answer
2k views

Interstellar Image Effects

I'd like to know how to create this type of gravitational lensing effect in an image (here are some star fields from the hubble) "I wrote down the equations and I tested them in Mathematica by ...
5
votes
2answers
817 views

How to see phase difference of two pendulum

i want to see the simulation of two uncoupled Simple Harmonic Motion (SHM) pendulum with different Lengths and released at different initial displacement angles. in this case adding one more pendulum ...
3
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2answers
676 views

How to make A simulation of 2-Dimensional Projectiles

Lets say two cannon is fired at different initial position, initial angle and initial speed. let say initial speed,angle and position for projectile 1= ...
-2
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1answer
428 views

Simulating a Wave Pulse

How to construct a code that superimpose n=10 one dimensional sinuisodal waves. each with an angular frequency ...
4
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0answers
416 views

How to do multi-agent modeling?

There are tons of examples here: http://demonstrations.wolfram.com/topic.html?topic=multi-agent+modeling&limit=20 But I been unable to find a good guide explaining what is the recommended ...
1
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1answer
322 views

Ball rotating in a Turntable

I made a turntable to make some experiments and make some studies about Coriolis and Euler forces acting in different frames of reference. ...
12
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4answers
3k views

How to make a Cahn–Hilliard model GIF

The question derived from @Jason B 's answer.I wanna make it but don't how to do.But we can get some rule about the GIF The change of the total pixel is very small. ...
9
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1answer
364 views

3D orbits of moons around their respective planets

I have seen a lot of solar system models (both animated and not), but I am trying to replicate the same thing with moons. Either just one planet and its lunar system or the our whole solar system with ...
20
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1answer
1k views

How best to simulate n-body systems in a functional way?

I want to simulate a N-body system in the most functional way possible. The system I'm modeling are metallic colloidal particles in a solution of peroxide water, as here http://arxiv.org/pdf/1502....
3
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1answer
506 views

Generate a simulated covariance matrix

I am working on a problem where one of the input variables is the level of covariance between the entries in a particular matrix. To simulate this problem in Mathematica, I will need to feed my code ...
4
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2answers
384 views

Confining/Periodic boundary conditions implementation for 2D Random Walker

I am new to Mathematica, and am having trouble implementing confining boundary conditions for a random walk simulation confining the walker to a pre-defined region (periodic boundary conditions would ...
6
votes
1answer
339 views

Battery charge simulation not clipping properly as it iterates

My code for simulating a batterylevel-state throughout a year in 15min-steps doesn't work. There is a certain list-inputs which simulates the charge state and the batterylevel-state, additionally ...
4
votes
2answers
678 views

Roulette simulator for a particular series of events

I'm new to Mathematica, and I would like to simulate the game of roulette. I want to bet like \$1 on the opposite color every time four reds or four blacks come up. I would like to know if I will ...
10
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2answers
294 views

Evolution of a trait in an asexual population (performance tuning)

I just coded a simple simulation module that looks at the evolution of a continuous trait in a haploid asexually reproducing population under density dependent competition in discrete time (i.e. non-...
1
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0answers
126 views

Multivariate Path Construction using Sobol numbers

I am sharing my code,which I have tried to perform as per the instruction mentioned below. Please correct it so that I could get my output. Instruction: Use the first m dimensions of the Sobol vector ...
10
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7answers
4k views

How to model rolling a pair of dice 100 times (Monte Carlo)

Like the title says, I'm having trouble trying to write out a function that will find the probability of finding the sum of a pair of dice 100 times to find the probability of each sum of 2,3,4,5...up ...
4
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1answer
136 views

Impact Crater Sim. with added criteria

I have been trying with out success to edit this impact crater simulation script into producing a variable which calculates crater density. In addition I have been trying to figure out how to ...
1
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1answer
574 views

How to simulate Multifractional Brownian Motion?

The maximum I would ask, is hints, how to model MFBMotion. Link to paper Firstly, i wanted to simulate in MATLAB that code: ...
2
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2answers
159 views

How to create a bar graph that evolves in time to monitor a simulation

I imagine a random process that proceeds as follows: Suppose there are $n$ dice. ($n$ is pretty big). They exist in an arena. They are all bouncing around. They start in a random configuration. If ...
2
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2answers
563 views

Solving coupled first-order autonomous differential equations

I am trying to run a simulation of a circuit to observe chaotic behavior, and have obtained a set of differential equations from an analysis of the circuit. I thought perhaps I could produce a plot ...
5
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2answers
2k views

Simple Monte Carlo simulation

I want to find the Monte Carlo simulation of the integral $$\int_0^1 \sqrt{1-x^2}\mathrm dx$$ The Cesàro mean is $$I_n=\frac1n\sum_{k=1}^{n} f(U_k) $$ I want to plot the scatter plot ((1,$I_1$)(2,$...
5
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2answers
1k views

Evaluation problems with NDSolve using the fixed step ExplicitEuler-Method

Motivation I am using Mathematica to implement System Dynamics (SD) models, e.g. differential equation models as applied to management/economic problems following the "methodology" of Jay W. ...
1
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2answers
408 views

Simulation of LogNormal process for an asset pricing

I'm new to Mathematica programming, so forgive my rather unsophisticated question. I need to simulate 5000 "walks" of a process value (of a stock) that starts from its current value, at ...
3
votes
1answer
101 views

How to deal with Part in a function?

I need to iterate several functions such as {3 x[[1]]^2 + x[[2]], x[[2]], x[[3]]}, {Exp[x[[4]]], x[[2]], x[[3]], x[[4]]},etc. ...
0
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1answer
130 views

My simulation is not never finishing and it is taking so much time?

I am running simple code which involves calculation of two first order differential equations.It is taking so much time and i am unable to get the results as the simulation is never finishing. ...
3
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1answer
191 views

How to speed up a system simulation?

I need to simulate a series of nonlinear (and linear) with thousands of state variables. Here is a simple linear example ...
1
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1answer
87 views

How would I go about simulating conditional random birth 100 times?

So I have the following scenario: Assume you have this organism that reproduces by itself. An organism either reproduces 0, 1, 2, or 3 organisms at a time. Assume they're asexual and reproduce only ...
46
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1answer
950 views

Random polyhedra walk

I would like to recreate ssch's random polyhedra random walk, which he posted in the chat. For convenience here it is again: This is my best attempt so far: You can download the notebook with the ...
7
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3answers
1k views

How to define a distribution that 90% of the time gives me 0?

This maybe a simple question, but I am just stuck with it. I want to do some simulation, say with 0.9 probability, I get a 1, and 0.1 probability get a 0. How would I do that? Where should I start? ...
4
votes
1answer
151 views

Adding extinction factor to Monte Carlo analysis

I'm looking to add an absorption component to this Monte Carlo analysis, essentially I want there to be a 1% chance that a photon gets absorbed at each event as it travels through the medium, once the ...
2
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2answers
601 views

Random walk using Module [closed]

I want to create a random walk using Module. The walk start at {0, 0}. At every step, x ...
9
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3answers
1k views

Simulate random data with correlation

I would like to simulate some random data e.g. between 0 and 1, but with a given correlation. In other words some data where the correlation between two datasets is e.g. a constant or within a give ...
0
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0answers
205 views

Simulation of the semicircle Wigner Theorem

Let's begin with some termes: For $1\le i<j<\infty$ let $X_{i,j}$ be independant and indentically distributed (i.i.d) real random variables with mean $0$ and variance $1$ and set $X_{j,i}=X_{...
9
votes
2answers
4k views

How to set up a simple Monte Carlo simulation?

there is a 1% chance that there will be a scattering event, if there is a scattering event the direction of scattering will be determined by a random sample of the custom[a_] function and if there is ...
1
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1answer
143 views

Find maximum Log likelihood for repeated random variates

I have the following code ...
38
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3answers
3k views

Computational Bayesian analysis in Mathematica: Any plans to develop MCMC?

Does anyone know if there are any plans to develop an MCMC capability in Mathematica? My reasoning for asking is that as it stands, I can't seem to find any 'out-of-the-box' functions/capabilities ...
1
vote
1answer
406 views

Simulate a polygon bouncing with collision detection inside a circle/polygon

Simulate a polygon bouncing with collision detection inside a circle/polygon. the example can be see in help page by searching WhenEvent; ...
9
votes
1answer
398 views

Solving 2-D Mechanical Systems

I'm trying to use Mathematica to solve a particular 2-d mechanical system. The system comes from "DESIGN AND OPTIMIZATION OF AN EIGHT-BAR LEGGED WALKING MECHANISM IMITATING A KINETIC SCULPTURE, “WIND ...
3
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0answers
161 views

How to control pedestrians to enter the simulation region with random functions?

I am working on simulating crowds of a cross-typed region, given that pedestrians entering from 4 gates of north, east, west and south, ...
0
votes
1answer
96 views

How can I use manipulate on multiple lists within a function?

So I have my N-Body Problem set up like so, and I can plot it in ListPointPlot3D, but I cannot figure out how to stick this into a manipulate function. ...
4
votes
1answer
531 views

Monte Carlo Volume Calculation and Speed Up

I am trying to do a Monte Carlo area calculation for an irregular area defined by: $$0 \le x \le 1, 10 \le y \le 13, y \ge 12 \cos(x), y \ge 10 + x^3$$ I used the code with modifications (so I can ...
0
votes
1answer
64 views

Simulating from Custom Function

I am going through an old research paper and I am stuck in one area of the coding. I'll spare you with most of the details but the function I want to simulate from is a complicated multivariate beta ...